Open AccessInterference-free hybrid fs/ps vibrational CARS thermometry in high-pressure flames
Author(s) -
Hans U. Stauffer,
Kazi Arafat Rahman,
Mikhail N. Slipchenko,
Sukesh Roy,
James R. Gord,
Terrence R. Meyer
Publication year - 2018
Publication title -
optics letters/optics index
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.524
H-Index - 272
eISSN - 1071-2763
pISSN - 0146-9592
DOI - 10.1364/ol.43.004911
Subject(s) - optics , interference (communication) , materials science , refractive index , physics , telecommunications , computer science , channel (broadcasting)
Interference-free hybrid femtosecond/picosecond vibrational coherent anti-Stokes Raman scattering (CARS) of nitrogen is reported for temperature measurements of 1300-2300 K in high-pressure, laminar H 2 -air and CH 4 -air diffusion flames up to 10 bar. Following coherent Raman excitation by 100 fs duration pump and Stokes pulses, a time-asymmetric probe pulse is used for the detection of spectrally resolved N 2 CARS signals at probe delays as early as ∼200-300 fs. This allows for full rejection of nonresonant contributions while being independent of collisions for single-shot precision of ±2% at elevated pressures. The effects of collisions at longer probe-pulse delays are also investigated to determine the feasibility of varying the detection timing from 200 fs to 100 ps.